From e4a6190fd49a4f0f89663d56021659d37d5a2a96 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Mon, 9 Jun 2025 14:40:24 -0700
Subject: [PATCH] tests: add a new test for the ClangImporter

Add a test case for shadowing definitions that are often used for
retraoctive aliasing and forward compatibility.
---
 .../ClangImporter/Inputs/custom-modules/module.modulemap | 4 ++++
 test/ClangImporter/Inputs/custom-modules/versioning.h    | 9 +++++++++
 test/ClangImporter/versioning.swift                      | 7 +++++++
 3 files changed, 20 insertions(+)
 create mode 100644 test/ClangImporter/Inputs/custom-modules/versioning.h
 create mode 100644 test/ClangImporter/versioning.swift

diff --git a/test/ClangImporter/Inputs/custom-modules/module.modulemap b/test/ClangImporter/Inputs/custom-modules/module.modulemap
index 2bd2627191949..89ccced682ba0 100644
--- a/test/ClangImporter/Inputs/custom-modules/module.modulemap
+++ b/test/ClangImporter/Inputs/custom-modules/module.modulemap
@@ -279,3 +279,7 @@ module "Weird C Module" {
 module Aliases {
   header "Aliases.h"
 }
+
+module RetroactiveVersioning {
+  header "versioning.h"
+}
diff --git a/test/ClangImporter/Inputs/custom-modules/versioning.h b/test/ClangImporter/Inputs/custom-modules/versioning.h
new file mode 100644
index 0000000000000..dcc6bb0840ee7
--- /dev/null
+++ b/test/ClangImporter/Inputs/custom-modules/versioning.h
@@ -0,0 +1,9 @@
+#pragma once
+extern const int kVersion;
+extern const int kVersion1;
+extern const int kVersion2;
+#if OLD_DEPLOYMENT_TARGET
+#define kVersion kVersion1
+#else
+#define kVersion kVersion2
+#endif
diff --git a/test/ClangImporter/versioning.swift b/test/ClangImporter/versioning.swift
new file mode 100644
index 0000000000000..a5077b92ecd1f
--- /dev/null
+++ b/test/ClangImporter/versioning.swift
@@ -0,0 +1,7 @@
+// RUN: %target-typecheck-verify-swift %s -I %S/Inputs/custom-modules
+// XFAIL: *
+
+// expected-no-diagnostics
+
+import RetroactiveVersioning
+let _ = kVersion